This proposal requests $102,390 to purchase instrumentation which updates and increases the capabilities of an in-place, in-use Mass Spectrometer. The addition of the Fast Atom Bombardment Technique and the addition of desorption chemical ionization are the primary aspects of the upgrade. The upgraded Mass spectrometer will then serve a group of users far more effectively than it can at present. The user group includes synthetic organic and bioorganic chemists. Research conducted by this group includes synthesis of biologically active substances (prostaglandins, leukotrienes, thromboxanes, blood group substances, immunostimulators, antibiotics, proteins, sugars, hormones, nucleic acids), structural determination of natural products and synthetic intermediates, examination of biological pathways and intermediates (shikimate, phosphorylations; enzyme substrate complexes), and characterization of enzyme prosthetic groups (rion-sulfur and iron-sulfur-molybdenum complexes). The instrumentation requested will be used to provide sensitive and more timely identification of chemical species involved in these studies.